[Clinical, pathological and electron microscopic observation of cardiac myxoma of the right atrium].

Five cases of cardiac myxoma of the right atrium and 1 case of myxosarcoma which involved both left and right atria are reported. Clinical manifestations were palpitation, shortness of breath, systolic and diastolic murmurs at the apical or tricuspid area, etc. Evidence of right atrial enlargement was shown on X-ray film. Echocardiographic examination was highly valuable in the diagnosis of this disease. The morphology of the myxoma of the right atrium was similar to that of the left one. The former was larger and heavier than the latter. Hemorrhage and necrosis inside the tumors were usually more severe in right atrial myxoma than the left. The clinical and pathological features (gross, histological and ultrastructural) are briefly discussed. In this series, 1 case of right atrial myxoma was complicated by alveolar cell carcinoma, but the histological changes of the two tumors were totally different.